The invention relates to an apparatus and method for controlling and monitoring wafer processing. More specifically, the present invention incorporates a bi-directional interface and communication protocol that may allow a wafer processing system to control and communicate with a detector, such as an external endpoint detection system.
As the demand for semiconductor devices continues to grow, semiconductor manufacturing equipment, e.g., wafer fabrication chambers are enhanced to increase productivity and to integrate the ever increasing number of diverse wafer processes into the chambers. One approach for promoting efficiency is to increase the number of chambers that are monitored by a wafer processing system. However, increasing the number of chambers may require extensive modification to the wafer processing system.
For example, FIG. 1 illustrates a conventional substrate (wafer) processing system which may comprise a controller 110, an endpoint detection system and one or more chambers 130a-130n. Generally, the controller 110 is tasked with the responsibility for controlling and monitoring the various etching processes or routines that are conducted within the chambers. However, to assist the monitoring function of the controller, an endpoint system 120 is coupled to the chamber to provide detection of the end of a particular process or step (endpoint). This endpoint detection system can be implemented using different technologies to detect different thresholds that are representative of an endpoint condition, e.g., the use of optical equipment to detect the etch depth. Since there are numerous wafer processing techniques, there are equally numerous types of endpoint detection systems. An example of such an endpoint point detection system includes Applied Materials"" xe2x80x9cH.O.T.xe2x80x9d (High Optical Throughput) Endpoint system. However, it should be understood that the present invention is not limited to any particular type of endpoint detection system.
If an endpoint system detects a condition within the chamber that is representative of the end of a particular process, a control signal is generated and communicated to the controller 110. In response to such a control signal, the controller will then terminate the current process within the relevant chamber. If applicable, the controller 110 can then start the next process and so on.
Typically, the communication between the controller 110 and the endpoint detection system 120 is implemented using direct communication lines, e.g., unidirectional communication lines. These communication lines allow various control and data signals to be passed between the controller and the endpoint detection system. More specifically, these signals may provide information concerning the status within the chamber, e.g., the start of a particular etching routine, the end of a particular etching routine, the identification number of the etching routine that is currently running in the chamber and the like.
To illustrate, if eight unidirectional communication lines are employed for the endpoint detection system (two lines for control signals and six lines for data signals), then it is possible to communicate a total of 26 (1-62) xe2x80x9calgorithm IDxe2x80x9d to the endpoint detection system 120 from the controller 110. More specifically, chamber processing is typically defined by a xe2x80x9crecipexe2x80x9d, whereas endpoint processing is typically defined by an xe2x80x9calgorithmxe2x80x9d or xe2x80x9croutinexe2x80x9d. Thus, each recipe step (substrate processing step) that employs external endpoint detection contains an algorithm ID that identifies the algorithm to be executed by the external endpoint detection system. It is the algorithm ID that is communicated via the six lines from the controller to the external endpoint detection system.
In operation, the controller 110 communicates to the endpoint detection system that a particular etching routine (or xe2x80x9cetch recipexe2x80x9d) will initiate in the chamber which, in turn, will require a particular endpoint detection algorithm for detecting the end of the etching process. The controller then uses one of the control lines to communicate the start of the etch routine (e.g., RF plasma on/off) to the endpoint detection system, while the other control line is used by the endpoint detection system to communicate the detection of the end of the etching routine.
Thus, an increase in either the number of endpoint detection routines or the number of chambers, will cause a corresponding increase in the number of direct communication connections with the controller 110. Unfortunately, this communication architecture is cumbersome in handling expansion, e.g., placing more chambers under the control of the controller. Specifically, the controller may require substantial modification by adding more communication ports and/or modifying the necessary software.
Therefore, a need exists in the art for a bi-directional interface and a communication protocol to allow a wafer processing system to control and communicate with an external endpoint system.
The present invention incorporates a bi-directional interface and a communication protocol that may allow a substrate processing system, such as a wafer processing system to control and communicate with an external endpoint system. More specifically, the present wafer processing system comprises a controller and an endpoint detection system that are coupled together by an interface, such as a RS-232 interface.
Furthermore, a SEMI Equipment Communications Standard (SECS) compliant communication protocol is employed to effect communication between the controller and endpoint detection system to increase wafer processing information exchange and data exchange. This information exchange is implemented by passing a plurality of messages between the controller and the endpoint detection system. The unique functions of the messages are defined in the message header.
The present hardware and software architecture increases system functionality and reduces demand for hardware resources and software maintenance overhead. Furthermore, the present bi-directional interface and communication protocol can be employed to increase wafer processing information exchange and data exchange between the controller and the external endpoint detection system.